Hi Rebecca. I just downloaded and installed the client. Not a peep from Windows Defender. Where did you find it? You should download it from: https://www.qcsalon.net/
As for how the programme works with JAWS -- I haven't had time to find out as when I was all up to playing last year it wouldn't work on my machine. Not a JAWS problem at all. But when you install the client it will open the Read Me file, unless you uncheck the box, and I suggest starting there and just reading the instructions. The system is designed to be accessible, so using it with your screen-reader of choice shouldn't be too challenging. For answers to frequently asked questions about this list visit: http://www.jaws-users.com/help/